Analog to digital conversion architecture is a functional realization of a process by which any analog signal can be converted into corresponding digital signal. The conversion process can be implemented either as continuous operation or as continuous cycles of operation. In the first case the process comprises of continuous operation of a method of analog to digital conversion which converts instantaneous values of an analog signal into a sequence of approximate digital values. In the second case the process comprises of a continuous cycles of operation of a method of analog to digital conversion which samples the analog signal into a sequence of analog values and converts each analog value into a digital value producing a sequence of digital values which form the digital output signal. In either case the method of analog to digital conversion which converts an analog value into a digital value comprises of a number of functional units each responsible for producing one or more number of bits as a part of overall digital value. When a method produces output bits simultaneously the architecture that uses such method is called parallel architecture. Similarly when a conversion method comprises of a single functional unit which in a number of cycles produces a sequence of output bits which when concatenated forms the overall digital value, the architecture that implements such method is called serial architecture. And an architecture, which uses a method in which a number of functional units are connected in series such that the output bits of each unit produced at different instant of time form the overall digital value, is called pipelined architecture. Besides serial, parallel and pipelined, there are other architectures as well and every architecture has its own advantages and disadvantages. This invention introduces an architecture called Domino Architecture, which is an improvement on pipelined architecture.
In pipelined architecture, the conversion method comprises of several conversion stages. In each conversion stage a functional unit samples the stage input signal, converts the sampled analog value into output bits of approximate digital value, converts the digital value back to analog value, finds an error by computing difference between original analog value and analog equivalent of approximate digital value and amplifies the error before feeding it into the following stage. Hence each functional unit comprises of a sample and hold function, analog to digital conversion function, digital to analog conversion function, analog subtraction function and amplification function. In domino architecture the digital to analog conversion function, subtraction function and amplification function required inside each functional unit are eliminated and the digital signal produced by each functional unit is directly fed into other functional units.